evans



Feb. 7, 1956 J. P. r-:vANs 2,733,622

PREDETERMINED- 'PORQUE RELEASE SOCKET AWRENCH Filed .March 19l 1954 2 Sheets-Sheet l Nom IN VEN TOR.

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Feb. 7, 1956 J. P. EVANS PREDETERMINED 'PORQUE RELEASE SOCKETAWRENCH Filed March 19, 1954 2 Sheets-Sheet 2 IN V EN TOR.v QggsEba/e;

Y Figure 3;, y "fFigure 7 isa.sectionalA view taken ongline`7,-- 7.of -Fi'gure 3 and'looking in the direction of the arrows;

United States Patent 2,733,622' PREDEIERMINEDTORQUE RELEASE SOCKET WRENCH Jacques P. Evans,`San Antonio, Tex. Application March 19, 1954, serial No. 417,245

f z claims. (cl. :s1-52.4)

fThisinvention relates to tools and more particularly to a torque tool to be employed as a wrench.

It isfan'object of this invention to providea torque wrench in which a positive indication of the torque applied tofthe nut or bolt vto be tightened is felt when the torque reaches a predetermined value, and any further movement of the wrench to apply further torque to the bolt or nut merely results in the wrench being inoperative to transmit the torque to the nut er belt.

It is a further object of this invention to provide a wrench which is designed to limit the torque applied in either fdirection, left or right, by a simple setting which predeterminesthe torque value'which may be applied to the; nut or bolt to be tightened and thereby prevents the applicationof unequal pressure to a plurality ofy 'nuts or bolts where-a constant torque value or degree of tightness is desired,fand at the 'same time avoids stripping the threads from the nut or bolt. Ai still further object of this invention is to provide `a t'orqucwrench in which the parts have been'properly hardened' sthat the `wrench will not -require frequent calibration,'as`is the case in many of the present torque 5 wrenches,and in 4which theV4 calibration ofthe wrench is easily effected andthe-wre'nch is adaptable to any range l calibration in inchor foot pounds; s i uAnother and 'still' further object of this invention is to provide'atorque wrench which may bev manufactured to accommodate any present socket wrench drive by merely increasing ordecreasing the size of the wrench. l x ffAlso, the torque wrench' of the present invention is capable ofy economical manufacture, employs a minimum numberrofworkingparts `s o as to'be'compact, and which is rugged andi4 capable of constant use over long periods without-anticipation of failure in the function of` the torque .twrench. Further, the present torque wrench `may beA easily`disa`ssembled and assembled to replace any parts whichmaybecomewornwith aV minimum'of effort and without -`the `requirement -of expert knowledge `of mechanics. i 'i Otherobjects and' advantages will become apparent from the: `following ldetailed description, forming the specification; and takenin'conjunction with the accompanying drawings,wherein;il j i ,JL Fig'u'rel is atpj plan viewof 'the torque wrench ernbodyingthis invention;4 v

,Figure'Z is' a partial sideelevational view of' the @Figure 3 'iseawertical sectional View through thehous ingrandfadjusting head, shownjpartially inelevation; vfr Figurev4isca1`sectionalview-similar to Figure 3 but showingthe `parts `within the housing in elevation;

figur-e, 5 is va fragmentary cross sectional view of the adjustingocapgshowing its relation to theliousing after havingbeen rotated onelfullturngv l w "Figure 6 is a sectionalview taken,` online 6-6 of within the housing, on a somewhat enlarged scale, showing a modified structure. With continued reference to the drawings, thereVV is shown a torque wrench, generally indicated at 10, which comprises a housing, generally indicated at 12 4of vcylindrical shape and having an annular chamber 14 therein, and a handle 16 preferably integral with the housing and extending laterally outwardly, therefrom. The elongated cylindrical handle 16 may be conveniently provided at Yits end remote from the `housing 12 with a roughened or knurled portion 18 to provide anon-slip grippingsurface for the hand of the user. i ff f The housing 12 includes a body 201 of `cup-shapehaving a cylindrical side wall and a rcircular bottoni L22 formed integrally therewith and closing one end of the chamber 14 while the end of the `body 2 0 remotefrrn the bottomor end wall 22 is closed by a circular c apj2'4 which defines a face plate for the wrench 10 a nd i,s 'se-` cured to the body 20 by screws 26which are receivedin countersunk apertures in the cap Yor face plate 24 and enters registeringtapped openings in a ange 2 8 formed annularly about the `end of the body Z0 at the end thereof l remote from the end wall 2 2 and directed inwardly there-V shank orplug 32,` dependingly'carri'ed centrally uponjan v adjusting head, generally indicated at 34`so `as tAono'r-'i mally maintain the circular indexing plate or flange 36in spaced parallel relationoverlying the outer surface'jof thecap or face -plate 24. The'top surface 25 of the cap orface plate 24` is provided about its periphery with spaced inscribed index markings o r"lines`38 to indicate torque force in inches or foot pounds'with the markings `pressions or concavities 40 withoneo 3S stepped in increments o f ten units of measurement and preferably each line Vormark indicated with a Vnumerical iigure. `The 'cap orface plate 24 alsol'is provided upon its top surface 25 witha'pluialityof shallow dec ff the depressions or concavities 40 in alignment with y onefof the markings loaded plungers 42 and 44 carried in diametrically op-A posed `relation by thev plate or flange 36 'in' respective l bosses'46 and 4S formed ntegrally'with the plate`136 and i `upstanding therefrom.- The centrahknob or boss 50 fis Y to be gripped by the-fingers of the user to rotate the adV` i justing head 34` with'relation Ato the housing 12 andspecifically withrrelationpto the cap or face plate 24,j The plate or flange 36 is further Vprovided with a triangular projection or pointer 52 extending outwardly therefrom at a point about its periphery-so" as to register with the.

markings 38 tojgive a reading in the units of measure employedras the `adjustinghead 34 is rotated `inclockwise direction from a stop 54 formedY as a postor extension jecting `upwardly from the top thereof so 'astd project beyond the upper or outer top surface 25 of the face plate 2,7as,622 Y e Y 24 and is disposed also along the longitudinal center line of the handle 16. The stop 54 determines the starting position from which the adjusting head 54 may be r0- tated, and limits the rotation of the adjusting head to approximately one full rturn since the pointer S2 will contact the stop 54 in its path of movement.

T he end wall 22 of the housing 12 is provided with a central transverse opening 56 therethrough defining a bearing and having an enlarged annular recess S8 in which is accommodated a collar 60 formed on the shank 62 or' a socket wrench drive or driving member, generally indicated at 64. A squared end 66 of the driving member or drive 64 projects outwardly from theV outer face of the end wall 22 and in perpendicular relation thereto extending along the longitudinal axis through the housing 12 and the chamber 14. The squared end 66 has the usual spring pressed ball 68 (see Figure 9) adjacent the terminal end thereof to define securing means whereby a socket wrench may be detachably secured onto the squared end 66 which deiines a wrench socket receiving member. Y

The drive 64 extends into the housing 12 and has its longitudinal center line coincident with the longitudinal center line throughY the housing 12 and the chamber 14 so that the major portion of the drive is disposed within the chamber 14 coaxially thereof. The upper cylindrical shaft portion 70 of the drive 64 is rotatably received within the closed bore 72, defining another bearing for the drive, which Vopens to one end of the shank 32 of the adjusting head 34 remote from the knob 50 into the chamber 14 of the housing 12. Y

In order to maintain the drive or driving member `64,

Y in the housing 12 against longitudinal movement relative thereto, there is` provided aretainer plate 74 having a central opening or recess 76 in coaxial with the opening 56 and opening through the inner facethereof to rotatably receive the shank 62 ofthe drive 64 which extends beyond the collar .60 to the side thereof remote from the squared end 66, and also has a plurality of spaced countersunk openings therethrough to receive therein screws 78 which enter registering tapped openings in the internally raised annular boss 80 formed integrally with the wall 22 so as to secure the retainer plate to the surface of the boss 80 remote from the outer face of the end wall 22. It will be noted that the boss 80 is of a lesser diameter than the chamber 14 andextends therewithin and the retainer plate secured thereon is adapted to engage the side of thecollar 60 remote from the side adjacent the squared end 66 so as to retain the drive 64 in the housing 12 against longitudinal movement relative to the housing.

The retainer plate 74 is circular rin outline and is received within the central annular opening 82 formed in the circular slip clutch plate 84 formed as a part of the bossl80 with the thickness of the retainer plate being less than that of the Vboss 80. The clutch platey 84 is provided along its at face remote from the end 22 with'a plurality of teeth 86 which are adapted to engage with the teeth 88 formedalong the periphery of the circular clutchplate 90 which is disposed in overlying relation to the clutch plate 84 and is of the same diameter, the diameters of the clutch plates 84 andt90 being the same as the diameter of the boss 80 formedon the endwall 22. Aclutch plate 90 isv provided with a square opening 92 therethrough which is coaxial with the openings 56 and 76 to receive therein a squared section 94 formed on the drive 64 between the shaft portion 70 and the shank 62 and extending from adjacent the top surface of the retaining plate 74 to beyond the end face ofthe clutch plate 90 Vremote from the end face carrying the teeth 88.

Y Thus, the drive 64 Vis operatively connected Yto the clutch plate 90 thereby permitting the movement of the clutch plate 90 with the rotationof the drive 64 as the wrench is applied to the nut or bolt (not shown) to be tightened.

A coilspring 96 surrounds the drive 64 and is seated on the end face of the clutch plate 90` remote from the end face carrying the teeth 88 and is retained at its other end by a washer 98 carried on the shaft portion 70 of the drive 64 adjacent the inner surface of the cap or face plate 24. lt will be noted that the end face of the externally threaded shank 32 of the adjusting head 34 will contact the surface of the washer 98 remote from the surface against which one end ofthe coil spring 96 bears. The coil spring 96 is preloaded by the use of a washer' 98 so that it resiliently urges or yieldingly moves the clutch late 99 into engagement with the clutch plate 84 and the spring load of the spring 96 maybe increased by rotating the adjusting head 34 in a clockwise direction to a value indicated by the markings 38 on the topV surface 25 of the face plate 24. The. action of the adjusting head 34 when rotated in a clockwise direction to load the spring 96 to a predetermined value has been fully discussed hereinberore with respect tothe action of the spring urged pins or plungers 42 and` 44 and their successive engagement in the concavities 40 to not only indicate movement to successive lines or markings 38 but also Yto'retain the adjusted position against displacement. Y

It will be appreciated, that the initial preloaded value of the coil spring 96 may be changed by theadditionrof more washers 98 whereby the markings 38 will be correspondingly changedY in their value in direct proportion thereto, and in proportion to the spring loadingon the spring 96. y

When the torque wrench` 10 is put in useto tighten a nut or bolt, and a suitably sized socket wrench, not shown, is deatchably secured onto the squared end 66 of the drive 64, the knob 50 of the adjusting head 54 may be gripped by the fingers of the operator and the adjusting head rotated in a clockwise direction to indicate the amount of torque he wishes to apply to the nut or bolt to be tightened. As hereinbefore indicated, rotationof the adjusting head 34 in a clockwise direction will cause compression of the coil spring 96 to a value indicated by the index defined by the markings 38 with the pointer 52 indicating the exact degree of compression imparted to the, spring 96. The spring 96 in turn transmits this predetermined resilient loadingl to the clutch plate 9,0 to advancek the clutch plate 90 into engagement Withthe clutch `plate84 so that themating teeth on the respective clutch plates are in mesh or engagement. The torque wrench, Vwith the suitably sized socket Ysecured upon the squared end 66 of the drive 64 will then be placed overthe nut or bolt to b e tightened, the knurled portion of the handle 16 then grasped by one hand of4 the operator and thehousing rotated in the proper direction, depending on whether the threading of the nut or bolt is right or left-handed, so that the movement of the handle will cause rotation of the housing 12 and the drive'64 due tothe operative conn nection between the drive and the clutch plate 90. The

rotation of the handle and housing will be continued to be imparted to the drive 64 until such time as the torque necessary to further tighten the nut or bolt to which the wrench is applied is equal to the resilient load selectively placed upon the spring 96. When these values are equal, or whenthe torque necessary-,to lfurther tighten the nut o r bolt to which the wrench is applied exceeds the resilient loading of the spring 96, Ythe clutch plate will have its teeth 88 ratchet about the -teeth 86 ofthe clutch plate 84 since the loading in the spring 96 will not be sufficient to hold the teeth 86 and 88 in engagement. Any further movement of thelwrench handle'r 16' in an effort to further tighten they nut or bolt to; which itis applied will merely result inthe slip action-of the clutch defined by the clutch plates 84 and 90 and the drive 64 will not have any further rotation'imparted thereto by rotation of the handle and housing of the torque wrench 10. It should be pointed out, that `the drive 64 isffreely rotatable within the housing 12. Y

In the resulting ratchet action between the clutch plates 84 and 90, this ratcheting'willjbe. transmittedthrough the housing 12 to the handle 16-and easily felt by the hand of the operator, who then will be apprised of the fact that the, nut or bolt to which the torque wrench 10 has been applied is no longer `operative to further tighten the nut or bolt and the degree of tightness is in accordance with the predetermined value selectively present by rotation of the adjusting head 34.

The illustration in Figure shows the relation of the lower surface of the flange 28 of the adjusting head 34 with the top or outer surface 25 of the face plate 24 when the adjusting head has been rotated to its maximum, that is one full turn in a clockwise drection, to show that a clearance will still be maintained between the ahsaa's joining faces of the ange 28 and the top surface 25-of f socket, not shown, is secured to the drive 64 at the squared end 66 thereof and the adjusting head 34 is set to the desired torque which exerts tension on the spring 96 which is transmittedl to the clutch plate 90. As the handle i fi 16 is turned to tighten the nut or bolt, the teeth 86 and 88 will remain engaged until the torque is set on the spring 96 by the adjusting head 34 obtains, at which time the drive 64 will remain stationary and any further movement of the handle 16 will cause the clutch plate'A 84 formed as an integral portion with the boss3 80'a`t its end remote from the outer face of the end wall `22, to rotate pushing the clutch plate 90 away therefrom thereby causing the operator to feel the ratcheting movement resulting between the clutch plates when the preset torque im value has been reached.

Thus, it will be noted that the clutch plate 84 is built in the housing 12 and will rotate therewith.

From the foregoing, it will be apparent that there has been provided a torque wrench 10 which comprises a rotatable housing 12, the housing 12 including a body 20 having a chamber 14 therein open at one end and a face plate 24 detachably secured to said body to close the one open end of the chamber 14, anadjusting head 34 rotatably carried on the plate 24, a drive 64 rotatably carried by the housing 12 and disposed within the body 20 in the chamber 14 coaxially with the longitudinal center line through the body and housing and having a socket receiving end 66 projecting beyond the body at the closed end 22 thereof remote from the open end, a fixed clutch plate 84 carried by and formed integrally with the body 12 and disposed within the chamber 14, a movable clutch plate 90 disposed' within the chamber 14 and operatively connected to the drive 64, yielding means in the form of the coil spring 96 operatively connected between the movable clutch plate and the adjusting head 34 to urge the movable clutch plate into engagement with the fixed plate, the adjusting head 34 being rotatable to selectively preset the loading of the yielding means 96 to cause rotationfof the movable clutch and be imparted to the drive 64 until the applied torque is equal to the preset value. Also, there is means defined by the retainer plate i .T i t 6 0.1 t ,:Ullrt': markings 38, against displacement frornthe selected prelset'position ofthe adjusting head 34. t

lt should be pointed out that the yielding means, coil spring 96, urges the movable clutch plate 90 into engage; ment` with the fixed clutch plate 84 whereby the movable platevwill be rotated upon rotation ofthe housing'12. In the modified structure shown in Figurel10, that part ofthe boss 80 formed as a circular slip clutch plate S4 has been replaced by a separate slip clutch gear 85 having formed therein teeth 87 adapted to mate teeth in-the clutch plate or gear 90. The teeth 87 ofy the slip clutch Y gear or plate 85 are arranged annularly aboutand define the wall of a recess 89 formed in the top `ofthe slip clutch gear or plate 85; A plurality of screws `78'` are received in equally spaced openings about theorecess 89 and extend therethrough into i suitably tapped openings in register with suitably tapped openings inthe boss 80 formed on the end wall 22. The boss 80' being of lesser height then the boss 80 `in the formof theinvention shown in Figures l through 9. It will also be noted that the openingsl through the slip clutch plate 85 wherein the plurality of bolts or screws 78 are received, are countersunk so that the heads of the screws V78' lwill not project above the surface of the recess 89.

The operation of the modified form of the invention shown in Figure 10 will be essentially the same as that of the torque wrench of Figures l `through 9,V and in addition, it will be apparent that the slip clutch plate or gear 85 Vwill be capable of removal from the chamber 14 inthe housing 12. t n l, t i Y t While there are shown and'described the preferred embodiment of the invention, itis to be understood that the structure is susceptible to change `and modification Within the practicabilityofthe invention and therefore should be'limited only by the scope of the claims appended hereto.

'What is claimed is:

l. A torque wrench comprising a hollow cylindrical body having a bottom wall closing one end thereof, a boss on the inner surface of said bottom wall extending into said body in concentrical relation about the longitudinal axis of said body to define a fixed clutch member, a cap closing the other end of said body, said bottom wall having an opening transversely therethrough concentric about the longitudinal length of said body, a plug thereadedly engaged in said cap in axial alignment with said opening and for advance through said plug toward said fixed clutch member, said plug having a socket therein opening through the end thereof adjacent said bottom wall 64 disposed within the chamber 14 and carried by the body 20 to retain the drive 64 against longitudinal movement with respect to the housing 12. Also, the plurality of markings 38 inscribed upon Ythe face plate 24 on the outer face 25 thereof defines a dial and a pointer 52 carried by the adjusting head 3'4 to cooperate with the dial to indicate the amount of load placed upon the yield- V termined value indicated upon the dial defined by the and in axial alignment with said opening to define along with said opening in said bottom wall spaced axial aligned bearings, a drive member mounted in said bearings for rotation about its longitudinal axis, a rotatable clutch member mounted on said drive for rotation therewith and movement longitudinally thereof into frictional engagement With'said fixed clutch member, a disc mounted on said drive for movement longitudinally thereof and engageable by said one end of said plug for movement longitudinally of said drive as said plug is advanced through said cap, a compression coil spring wrench concentrically about said drive member and engaging said rotatable clutch member into said disc at its opposite ends, a knob carried by said plug at its other end remote from said socket whereby rotation imparted to said knob will cause said plug to be advanced through said cap toward said fixed clutch member, spring loaded plungers carried by said knob and engaging said plug for maintaining said knob in a selected position of rotation and maintaining said spring under a selected tension imparted thereto by the advance of said plug and movement of said disc longitudinally of said drive member to place .said rotatable clutch member Yinto frictional engagement thereto Ato cause rotation of said drive through said frictionally engaged clutch members` until a torque applied to said'drive equals the preset tension of said spring.`

2. A torque wrench comprising a hollow cylindrical body having a bottom wall closing one end thereof, a

boss on the inner surface'of said bottomY Wall extending` lbottom wall and in axial alignment with said opening to define along with said opening in said bottom wall spaced axial aligned bearings, a drive member mounted in said bearings Vfor rotation about its longitudinal axis, a rotatable clutch member mounted on said drive for rotation therewith and movement longitudinally thereof into fric' tional engagement with said xed'clutch member, a disc mounted on said drive for movement longitudinally thereof and engageable by said one end of said plug for movement longitudinally of said drive as said plug is Vadvanced through said cap, a compression coil spring wrench concentrically about said drive member and engaging said rotatable clutch member into said disc atits opposite ends, a knob carried by said plug at its other end Yremote from said socket whereby rotation imparted to'said knob will cause said plug to be advanced through said cap toward said fixed clutch member, spring loadedV plungers carried by said knob and engaging said plug for maintaining said knob in a selected position of rotation and maintaining said spring under a selected tension imparted thereto by the advance of said plug and movement of said disc longitudinally of said drive member to'place said rotatable clutch member intoY frictional engagement with said fixed member under the selected tension, and a handle connected to said body for imparting rotation thereto to cause rotation of said drive through said frictionally engaged clutch members until a torque applied to said drive equals the preset tension of said spring, said opening in said bottom wall formed with an enlarged angular recessin the bottom wall, a collar formed on said drive received in said recess to prevent longitudinalrmovement of said drive in one direction, and said fixed clutch member having a recess therein opening through the face thereof remote from said bottom wall and arranged in axial alignment with said opening and in communication with said opening, a retainer plate having an opening centrally therethrough through which said drive member projects, said plate being received in said recess and engaging said collar to prevent longitudinal movement of said drive in the other direction, and means for securing said plate to said fixed clutch memberl References Cited'in the file of this patent UNITED STATES PATENTS 1,537,629

Stuart May 24, 1955 

